Extending point-to-point/asynchronous transfer mode services to client computer systems

ABSTRACT

A method, apparatus, and system are provided for transmitting an Asynchronous Transfer Mode (ATM) cell from a server system to a broadband modem and forwarding the ATM cell from the broadband modem to a client system. According to one embodiment, a Broadband Modem Access Protocol (BMAP) unit is used to discover the identity of the broadband modem.

This is a division of application Ser. No. 09/182,585, filed Oct. 28,1998.

FIELD OF THE INVENTION

The present invention relates to broadband modems. More specifically,the present invention relates to a method and apparatus for extendingPoint-to-Point Protocol (PPP)/Asynchronous Transfer Mode (ATM) servicesto client computer systems.

BACKGROUND OF THE INVENTION

Broadband data transmission supports high bandwidth throughput throughthe use of multiple channels over a single transmission medium at onetime. Multiple channels are supported on the single transmission mediumthrough frequency division multiplexing. Broadband data transmissiontechnologies include Integrated Services Digital Network (ISDN) andAsymmetric Digital Subscriber Line (ADSL).

ADSL is a new modem technology that converts existing twisted-pairtelephone lines into access paths for multimedia and high speed datacommunications. ADSL supports data rates of up to 8 Mbps downstream tothe user and up to 1.5 Mbps upstream from the user. An ADSL circuitconnects an ADSL modem on each end of a twisted-pair telephone line,creating three information channels, a high speed downstream channel, amedium speed upstream channel, and a plain old telephone service (POTS)channel.

Current ADSL modems that support ATM network technology requiresufficient processing and memory resources in order to perform thenecessary ATM signaling procedures and segmentation and reassembly (SAR)functionality. In addition, in order to support a point-to-paintprotocol for connecting a client system to the Internet, ADSL modemsrequire sufficient processing and memory resources to run a Layer TwoTunneling Protocol (L2TP) over a User Datagram Protocol/InternetProtocol. The L2TP enables Internet service providers to operate virtualprivate networks (VPNs). FIG. 1 illustrates the modules that aconversational ADSL modem 100 supports in providing PPP/ATM services toa client computer system 160. The ADSL modem 100 supports a UDP/IP stack110 and a L2TP stack 120 on a first side that is connected to the clientcomputer system 160 via modem-client connection 150. The ADSL modem 100also supports an ATM protocol stack 130 on a second side connected tothe ADSL physical interface 140. The ATM protocol stack 130 includes anATM layer 131, segmentation and re-assembly layer (SAR) 132, ATMadaptation layer (ML) 133, and a signaling (SIG) layer 134. Datareceived from the ADSL physical interface 140 us processed by the ATMprotocol stack 130 on the ADSL modem 100 to retrieve raw data from thepayload of an ATM cell. Similarly, data received from the clientcomputer system 160 to be transmitted on the ADSL physical interface 140is processed by the ATM protocol stack 130 on the ADSL modem 100 toappropriately format the data into ATM cells.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings, in which thelike references indicate similar elements in and in which:

FIG. 1 is a block diagram illustrating the modules that a conventionalADSL modem supports to provide PPP/ATM services to a client computersystem;

FIG. 2 illustrates a network in which an embodiment of the presentinvention is implemented;

FIG. 3 is a block diagram of a computer system in which an embodiment ofthe present invention is implemented;

FIG. 4 illustrates a broadband modem access protocol unit implemented ina computer system according to an embodiment of the present invention;

FIG. 5 illustrates an ATM unit implemented in a computer systemaccording to an embodiment of the present invention;

FIG. 6 illustrates a broadband modem access protocol unit implemented ina broadband modem according to an embodiment of the present invention;

FIG. 7 illustrates the modules that a broadband modem and computersystem support to provide PPP/ATM service according to an embodiment ofthe present invention;

FIG. 8 is a flow chart illustrating a method for managing ATM cellsaccording to an embodiment of the present invention; and

FIG. 9 is a flow chart that illustrates a method for managing abroadband modem according to an embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 2 illustrates a network 200 in which an embodiment of the presentinvention is implemented. The network includes a first computer system210 and a second computer system 220. Data is transmitted between thefirst computer system 210 and the second computer system 220 viatransmission medium 250. The transmission medium 250 may be implementedby a twisted-pair telephone line utilizing ADSL technology, cable, orfiber optics. The data transmitted between the first computer system andthe second computer system 220 is formatted using ATM multiplexing andswitching method. The second computer system 220 is coupled to thetransmission medium 250 via a broadband modem 230. The broadband modem230 is coupled to the second computer system via a first connection 235.The broadband modem 230 may be, for example, an ADSL modem, a cablemodem, or other type of broadband modem. The first connection 235 may bean Ethernet connection, a Universal Serial Bus (Universal Serial BusSpecification, Revision 1.0, January 1996) connection, an IEEE 1394(IEEE Std. 1394-1995, Standard for a High Performance Serial Bus, August1996) connection, or other type of connection. The first computer system210 is coupled to the transmission medium via a second connection 225.The second connection 225 may be a connection to the transmission medium250 via a connection similar to the first connection 235 and thebroadband modem 230. Alternatively, the second connection 225 may be aconnection to an intermediary, such as a telephone company, that iscoupled to the transmission medium 250. Communication with theintermediary may be achieved through using a Synchronous Optical Network(SONET), Synchronous Digital Hierarchy (SDH), frame relay networkingprotocol, or other protocols.

According to an embodiment of the present invention, the broadband modem230 is a peripheral, whereby it operates as a communications peripheralrather than a networking node to the second computer system 220. Thebroadband modem 230 operates as an interface between the first computersystem 210 and the second computer system 220 without performing ATMsignaling procedures. The broadband modem 230 forwards ATM cellsreceived from the first computer system 210 to the second computersystem 220 without performing reassembly procedures to retrieve datafrom the ATM cells' payload. Similarly, the broadband modem 230transmits the ATM cells received from the second computer system 220 tothe first computer system 210 without performing segmentation proceduresto construct the ATM cell.

The first computer system 210 may be, for example, a server computersystem or an Internet service provider (ISP). The second computer system220 may be, for example, a client computer system such as a personalcomputer (PC) used at a home or office. It should also be appreciatedthat the data transmitted between the first computer system 210 and thesecond computer system 220 may be formatted using other multiplexing andswitching methods.

FIG. 3 is a block diagram of the computer system 220 in which anembodiment of the present invention is implemented. The computer system220 may be implemented as the second computer system 220 illustrated inFIG. 2. The computer system 220 includes a processor 301 that processesdata signals. The processor 301 may be a complex instruction setcomputer (CISC) microprocessor, a reduced instruction set computing(RISC) microprocessor, a very long instruction word (VLIW)microprocessor, a processor implementing a combination of instructionsets, or other processor device. FIG. 3 shows an example of the presentinvention implemented on a single processor computer system 220.However, it is understood that the present invention may be implementedin a computer system having multiple processors. The processor 301 iscoupled to a CPU bus 310 that transmits data signals between processor301 and other components in the computer system 220.

The computer system 220 includes a memory 313. The memory 313 may be adynamic random access memory (DRAM) device, a static random accessmemory (SRAM) device, or other memory device. The memory 313 may storeinstructions and code represented by data signals that may be executedby the processor 301. A cache memory 302 resides inside processor 301that stores data signals in memory 313. The cache 302 speeds up memoryaccesses by the processor 301 by taking advantage of its locality ofaccess. In an alternate embodiment of the computer system 220, the cache302 resides external of the processor 301. According to one embodiment,as illustrated, the ATM unit 500 may be implemented by software andreside in main memory 313 as a sequence of instructions. According toanother embodiment, the ATM unit 500 may also be implemented by hardwareas components coupled with the bus 320. According to another embodiment,the ATM 500 may be implemented as a combination of both hardware andsoftware.

A bridge memory controller 311 is coupled to the CPU bus 310 and thememory 313. The bridge memory controller 311 directs data signalsbetween the processor 301, the memory 313, and other components in thecomputer system 220 and bridges the data signals between the CPU bus310, the memory 313, and a first I/O bus 320.

The first I/O bus 320 may be a single bus or a combination of multiplebuses. As an example, the first I/O bus 320 may comprise a PeripheralComponent Interconnection (PCI) bus, a Personal Computer Memory CardInternational Association (PCMCIA) bus, a NuBus, or other buses. Thefirst I/O bus 320 provides communication links between components in thecomputer system 220. A network controller 321 is coupled to the firstI/O bus 320. The network controller 321 links the computer system 220 toa network of computers (not shown in FIG. 3) and supports communicationamong the machines. A display device controller 322 is coupled to thefirst I/O bus 320. The display device controller 322 allows coupling ofa display device to the computer system 220 and acts as an interfacebetween the display device and the computer system 200. The displaydevice may be a monochrome display adapter (MDA) card, a color graphicsadapter (CGA) card, an enchanced graphics adapter (EGA) card, anextended graphics array (XGA) card or other display device controller.The display device may be a television set, a computer monitor, a flatpanel display or other display device. The display device receives datasignals from the processor 301 through the display device controller 322and displays the information and data signals to the user of thecomputer system 220. A video camera 323 is coupled to the first I/O bus320. The video camera 323 operates to capture an image of an object. Thevideo camera 323 may be a digital camera having internal digital videocapture hardware that translates the captured image into image data. Thevideo camera 323 may be an analog video camera having digital videocapture hardware external to the video camera 323 that digitized thecaptured image into image data.

Connection 235 is coupled to the network controller 321. The connection235 represents the first connection 235 shown in FIG. 2. The connection235 may be an Ethernet connection, a USB connection, an IEEE 1394connection, or other type of connection. The network controller 321couples the connection 235 with the first I/O bus 320 and bridgessignals between the first I/O bus 320 and the connection 235. Abroadband modem 230 is coupled to the connection 235. It should beappreciated that the broadband modem 230 may be an ADSL modem, a cablemodem or other type of broadband modem.

A second I/O bus 330 may be a single bus or a combination of multiplebuses. As an example, the second I/O bus 330 may comprise a PCI bus, aPCMCIA bus, a NuBus, an Industry Standard Architecture (ISA) bus, orother buses. The second I/O bus 330 provides communication links betweencomponents in the computer system 220. A data storage device 331 iscoupled to the second I/O, bus 330. The data storage device 331 may be ahard disk drive, a floppy disk drive, a CD-ROM device, a flash memorydevice or other mass storage device. A keyboard interface 332 is coupledto the second I/O bus 330. The keyboard interface 332 may be a keyboardcontroller or other keyboard interface. The keyboard interface 332 maybe a dedicated device or can reside in another device such as a buscontroller or other controller. The keyboard interface 332 allowscoupling of a keyboard to the computer system 220 and transmits datasignals from a keyboard to the computer system 220. An audio controller333 is coupled to the second I/O bus 330. The audio controller 333operates to coordinate the recording and playing of sounds.

A bus bridge 324 couples the first I/O bus 320 to the second I/O, bus330. The bus bridge 324 operates to buffer and bridge data signalsbetween the first I/O bus 320 and the second I/O bus 330.

The present invention is related to the use of the computer system 220to manage a broadband modem. According to one embodiment, managing thebroadband modem is performed by the computer system 220 in response tothe processor 301 executing a sequence of instructions in main memory313. Such instructions may be read into memory 313 from anothercomputer-readable medium, such as data storage device 331, or fromanother source via the network controller 321. Execution of the sequenceof instructions causes the processor 301 to manage the broadband modem,as will be described hereafter. In an alternate embodiment, hardwiredcircuitry may be used in place of or in combination with softwareinstructions to implement the present invention. Thus, the presentinvention is not limited to any specific combination of hardwarecircuitry and software.

FIG. 4 is a block diagram of a broadband modem access protocol (BMAP)unit 400 according to an embodiment of the present invention. In apreferred embodiment of the present invention, the BMAP unit 400 isimplemented by software and resides in main memory 313 (shown in FIG. 3)as a sequence of instructions. It should be appreciated that the BMAPunit 400 may also be implemented by hardware as components coupled tothe bus 320 (shown in FIG. 3) or a combination of both hardware andsoftware. The BMAP unit 400 includes a modem identification unit 410.The modem identification unit 410 identifies and selects a BMAPcompliant broadband modem coupled to the connection 235 (shown in FIGS.2 and 3). According to the BMAP, the computer system 220 (shown in FIG.2) is initially set at a DISCONNECT state. While in the disconnectstate, the modem identification unit 410 transmits a DISCOVERY messageevery T_DISCOVERY seconds where T_DISCOVERY is a predefined period oftime. The modem identification unit 410 transmits the DISCOVERY messageusing a Media Access Control (MAC) layer multicast address until aDISCOVERY ACKNOWLEDGE message from a broadband modem is received. Uponreceiving the DISCOVERY ACKNOWLEDGE message, the modem identificationunit 410 learns the individual MAC address of the broadband modem andestablishes a binding with the broadband modem. When multiple BMAPcompliant broadband modems are coupled to the first connection 235, themodem identification unit 410 selects one of the broadband modems toestablish a binding with and uses its corresponding MAC address forsubsequent correspondences. The modem identification unit 410 transmitsa TERMINATE message to the BMAP compliant broadband modems that are notselected. Upon receiving the DISCOVERY ACKNOWLEDGE message, the computersystem 220 enters into a CONNECT state.

Non-BMAP compliant computer systems and broadband modems require thelocal IP network on the first connection 235 to be properly configuredas illustrated in FIG. 1. This typically requires that an IP address beassigned to the broadband modem before an end-to-end PPP connection canbe established. Home networks without routers and Dynamic HostConfiguration Protocol (DHCP) servers will require manual configurationof a static IP address. The modem identification unit 410 facilitatesmodem identification without requiring a user to manually configureaddresses.

A format negotiation unit 420 is coupled to the modem identificationunit 410. The format negotiation unit 420 operates to identify theformat in which the computer system 220 and the selected broadband modemshould use to format data transmitted between the units. The formatnegotiation unit 420 specifies a number of data formats in the order ofpreference that the computer system 220 is able to support in theDISCOVERY MESSAGE sent on the connection 235. The broadband modemspecifies the subset of data formats it is able to support in theDISCOVERY ACKNOWLEDGE message. The data formats that may be specified bythe computer system 220 may include ATM cells, cell header template andconcatenated cell payloads, virtual path identifier/virtual channelidentifier (VPI/VCI) and AAL5, or other data formats.

A binding maintenance unit 430 is coupled to the format negotiation unit420. The binding maintenance unit 430 operates to keep active a bindingbetween the computer system 220 and a selected broadband modem. While inthe CONNECT state, the binding maintenance unit 430 transmits a POLLmessage to the selected broadband modem every T_POLL seconds whereT_POLL is a predefined period of time. The binding maintenance unit 430monitors the first connection 235 for a POLL_ACK message sent inresponse to the POLL message. If the binding maintenance unit 430 doesnot detect a POLL_ACK message after issuing a predefined number of POLLmessages, the computer system 220 will re-enter the DISCONNECT state.Either the computer system 220 or the broadband modem may terminate abinding by sending a TERMINATE message to the other party. Uponreceiving the TERMINATE message, the computer system 220 or broadbandmodem will enter into the DISCONNECT state.

A power management unit 440 is coupled to the binding maintenance unit430. When the computer system 220 enters a power saving mode, it will nolonger be capable of generating regular POLL messages to the broadbandmodem. The power management unit 440 transmits a SLEEP message to thebroadband modem prior to it entering the SLEEP state. Upon receiving theSLEEP message, the broadband modem will enter into a SLEEP state anddisable its activity timeout until either a wake-up pattern is sent tothe computer system 220, or until the computer system 220 resumessending data or POLL messages to the modem. The power management unit440 also transmits a wake-up pattern to the broadband modem. Uponreceiving the wake-up signal from the broadband modem, the computersystem 220 will exit the SLEEP state.

A data transfer unit 450 is coupled to the power management unit 440.For data formatted as ATM cells, the ATM signaling procedures areperformed on the computer system 220. The data transfer unit 450transfers ATM cells to and from the broadband modem. For data formattedwith cell header template and concatenated cell payloads, duplicate cellheaders are removed with the rest of the operation remaining the same asdescribed above.

It should be appreciated that the modem identification unit 410, formatnegotiation unit 420, binding maintenance unit 430, power managementunit 440, and data transfer unit 450 may be coupled together in an orderdifferent than that shown in FIG. 4. The modem identification unit 410,format negotiation unit 420, binding maintenance unit 430, powermanagement unit 440, and data transfer unit 450 may be implemented usingany known circuitry or technique. In an embodiment of the presentinvention where the BMAP unit 400 is implemented in hardware, the modemidentification unit 410, format negotiation unit 420, bindingmaintenance unit 430, power management unit 440, and data transfer unit450 all reside on a single semiconductor substrate.

FIG. 5 is a block diagram of an ATM unit 500 according to an embodimentof the present invention. In a preferred embodiment of the presentinvention, the ATM unit 500 is implemented by software and resides inmain memory 313 (shown in FIG. 3) as a sequence of instructions. Itshould be appreciated that the ATM unit 500 may also be implemented byhardware as components coupled to the bus 320 (shown in FIG. 3) or acombination of both hardware and software. The ATM unit 500 includes anATM unit 510. The ATM unit 510 operates to perform the functions of cellconstruction, cell reception and header validation, cell relaying,forwarding and copying, cell multiplexing and demultiplexing, cellpayload type discrimination, and other functionalities. An SAR unit 520is coupled to the ATM unit 510. The SAR unit 520 segments andre-assembles data between the AAL convergence sublayer into the cellpayloads of an ATM cell stream. An AAL unit 530 is coupled to the SARunit 520. The AAL unit 530 defines the headers and trailers in an AALpacket. A SIG unit 540 is coupled to the AAL unit 530. The SIG unit 540sets up the virtual channels on which the ATM cell will be transmitted.

It should be appreciated that the ATM unit 510, SAR unit 520, AAL unit530, and SIG unit 540 may be coupled together in an order different thanthat shown in FIG. 5. The ATM unit 510, SAR unit 520, AAL unit 530, andSIG unit 540 may be implemented using any known circuitry or technique.In an embodiment of the present invention where the ATM unit 500 isimplemented in hardware, the ATM unit 510, SAR unit 520, AAL unit 530,and SIG unit 540 all reside on a single semiconductor substrate.

FIG. 6 illustrates a BMAP unit 600 implemented in the broadband modem230 (shown in FIGS. 2 and 3) according to an embodiment of the presentinvention. The BMAP unit 600 includes a modem identification unit 610.According to the BMAP, the broadband modem 230 is initially set at aDISCONNECT state. Upon receiving a DISCOVERY message from a computersystem, the modem identification unit 610 responds by transmitting aDISCOVERY_ACKNOWLEDGE message to the MAC address of the computer system.When the modem identification unit 610 receives DISCOVERY messages frommore than one computer system, the modem identification unit 610responds to only one of the DISCOVERY messages. Upon receiving theDISCOVERY message, the broadband modem 230 enters into a CONNECT state.

A format negotiation unit 620 is coupled to the modem identificationunit 610. The format negotiation unit 620 receives the identity of dataformats that the computer system is able to support from the DISCOVERYmessage. The format negotiation unit 620 specifies the subset of thedata formats that the broadband modem 230 is able to support in theDISCOVERY_ACKNOWLEDGE message that is transmitted to the computersystem.

A binding acknowledgment unit 630 is coupled to the format negotiationunit 620. In response to receiving POLL messages from the computersystem, the binding acknowledgment unit 630 transmits a POLL_ACK messageto the computer system. If there is no control or data messages receivedfrom the computer system after a third predefined period of timedetected by an activity timer of the broadband modem 230, the binding isdetermined to be broken, and the broadband modem will re-enter into theDISCONNECT state.

A power management unit 640 is coupled to the binding acknowledgmentunit 630. The power management unit 640 puts the broadband modem into aSLEEP state in response to receiving a SLEEP message from the computersystem. When a wake-up event such as an ATM incoming call arrives orupon receiving a DISCOVERY message from a non-binding computer systemwhile in the SLEEP state, the power management unit 640 of the broadbandmodem 230 sends a wake-up pattern recorded in the SLEEP message to thecomputer system and drives the broadband modem 230 into the CONNECTstate and starts its activity timer. If the activity timer expires, thebroadband modem 230 will re-enter the DISCONNECT state and make itselfavailable for other computer systems.

A data transfer unit 650 is coupled to the power management unit 640.The data transfer unit 650 transfers ATM cells between the transmissionmedium 250 (shown in FIGS. 2) and the connection 235 (shown in FIG. 2).

It should be appreciated that the modem identification unit 610, formatnegotiation unit 620, binding acknowledgment unit 630, power managementunit 640, and data transfer unit 650 may be connected together in anorder different than that shown in FIG. 6. The modem identification unit610, format negotiation unit 620, binding acknowledgment unit 630, powermanagement unit 640, and data transfer unit 650 may be implemented byany known circuitry or technique. In an embodiment of the presentinvention where the BMAP unit 600 is implemented in hardware, the modemidentification unit 610, format negotiation unit 620, bindingacknowledgment unit 630, power management unit 640, and data transferunit 650 all reside on a single semiconductor substrate.

FIG. 7 illustrates the modules that the broadband modem 230 and computersystem 220 support to provide PPP/ATM service according to an embodimentof the present invention. Unlike the conventional broadband modem 100illustrated in FIG. 1, the broadband modem 230 of the present inventionoperates as a communications peripheral rather than a networking node.The broadband modem 230 operates as an interface between the firstcomputer system 210 and the second computer system 220 withoutperforming ATM signaling procedures and SAR functionalities. Thebroadband modem 230 forwards ATM cells received from the computer system210 to the transmission medium 250 without performing segmentationprocedures to construct the ATM cell. Similarly, the broadband modem 230transmits the ATM cells received from the transmission medium 250 to thecomputer system 210 without performing assembly procedures to receivedata from the ATM cells' payload. An ATM unit 710 on the broadband modem230 also generates and verifies the header control (HEC) field in theATM cell for upstream and downstream traffic. According to an embodimentof the present invention, the traditional ATM signaling procedures onceperformed by the signaling stack 130 (shown in FIG. 1) on conventionalbroadband modems 100 are performed by an ATM unit 500 on the computersystem 220. Migrating the ATM signaling procedures onto the computersystem allows PPP/ATM services to be extended to client computer systemswithout requiring L2TP and UDP/IP to be run on broadband modems. Thisreduces the hardware required for broadband modems and reducesconnection and installation procedures necessary for extending PPP/ATMservices to client computer systems. It should be appreciated that whenthe data format negotiated between the broadband modem 230 and thecomputer system 220 is of the AAL5 format, the SAR unit 520 would beimplemented on the broadband modem 230 instead of the computer system220.

FIG. 8 is a flow chart illustrating a method for managing ATM cellsaccording to an embodiment of the present invention. At step 801, an ATMcell is transmitted from a server system to a broadband modem. Accordingto an embodiment of the present invention, the ATM cell may betransmitted over a telephone wire, a cable connection, or othertransmission media.

At step 802, the header error control (HEC) field in the ATM cell ischecked for corruption before forwarding the ATM cell to the clientsystem.

At step 803, the ATM cell is transmitted from the broadband modem to aclient system. According to an embodiment of the present invention, theATM cell may be transmitted to the client system via an Ethernetconnection, USB connection, IEEE 1394 connection, or other connection.

At step 804, the ATM cell is processed at the client computer system toretrieve raw data from a payload section of the ATM cell.

FIG. 9 is a flow chart that illustrates a method for managing abroadband modem according to an embodiment of the present invention. Atstep 901, a broadband modem that is connected to a computer system isdiscovered. According to an embodiment of the present invention,discover may be achieved by transmitting a discovery signal over aconnection and recording a media access control (MAC) addresscorresponding to the broadband modem that transmits a discoveryacknowledge signal in response to the discovery signal.

At step 902, a data format is negotiated with the broadband modem. Thedata formats may be negotiated by specifying a set of data formats thatmay be supported in the discovery signal, receiving a subset of dataformats that are supportable by the broadband modem in the discoveryacknowledge signal, and selecting one of the subset of data formats.

At step 903, a binding between the computer system and the broadbandmodem is maintained. According to an embodiment of the presentinvention, the binding is maintained by sending a poll message to thebroadband.

1. A system, comprising: a storage medium; a bus coupled with thestorage medium; a processor coupled with the bus; a BMAP unit and amodem identification unit coupled to the bus; a network controllercoupled with the bus; a broadband modem access protocol (BMAP)-compliantbroadband modem coupled with the network controller via a connection,wherein the broadband modem is identified and selected from a pluralityof broadband modems using said BMAP unit including said modemidentification unit corresponding to the broadband modem; and anAsynchronous Transfer Mode (ATM) unit, coupled with the bus, the ATMunit to perform at least one of the following: ATM signaling,segmentation, and re-assembly procedures on ATM cells forwarded betweenthe broadband modem and the network controller.
 2. The system of claim1, wherein the BMAP unit comprises at least one of the following: asoftware-based BMAP unit and a hardware-based BMAP unit.
 3. The systemof claim 1, wherein the BMAP unit comprises: the modem identificationunit to transmit a discovery acknowledge message to a Media AccessControl (MAC) address of a client system in response to a discoverysignal from the client system; a format negotiation unit coupled withthe modem identification unit, the format negotiation unit to receiveidentification of data formats; a binding acknowledgement unit coupledwith the format negotiation unit, the binding acknowledgement unit totransmit a poll acknowledgement message to the client system in responseto receiving a poll message from the client system; a power managementunit coupled with the binding acknowledgement unit, the power managementunit to put the broadband modem into a sleep state in response toreceiving a sleep message from the client system; and a data transferunit coupled with the power management unit, the data transfer unit totransfer the ATM cells between the broadband modem and the networkcontroller.
 4. The system of claim 1, wherein the ATM unit comprises atleast one of the following: a software-based ATM unit and ahardware-based ATM unit.
 5. The system of claim 1, wherein the ATM unitis further to perform at least one of the following: cell construction,cell reception and header validation, cell relaying, forwarding andcopying, cell multiplexing and demultiplexing, and cell payload typedescription.
 6. The system of claim 1, wherein the ATM unit comprises: asegmentation and reassembly (SAR) unit to segment and reassemble databetween an ATM adaptation layer (AAL) convergence sublayer into cellpayloads of an ATM cell stream; an AAL unit coupled with the SAR unit,the AAL unit to define headers and trailers in an AAL packet; and asignaling (SIG) unit coupled with the AAL unit, the SIG unit to set upvirtual channels to transmit the ATM cells.
 7. An apparatus, comprising:a bus; a network controller coupled with the bus; a BMAP unit includinga modem identification unit coupled to the bus; a broadband modem accessprotocol (BMAP)-compliant broadband modem coupled with the networkcontroller, wherein the broadband modem is identified and selected froma plurality of broadband modems using said BMAP unit including saidmodem identification unit corresponding to the broadband modem; and anAsynchronous Transfer Mode (ATM) unit, coupled with the bus, the ATMunit to perform at least one of the following: ATM signaling,segmentation, and re-assembly procedures on ATM cells forwarded betweenthe broadband modem and the network controller.
 8. The apparatus ofclaim 7, wherein the BMAP unit comprises at least one of the following:a software-based BMAP unit and a hardware-based BMAP unit.
 9. Theapparatus of claim 7, wherein the modem identification unit to transmita discovery acknowledge message to a Media Access Control (MAC) addressof a client system in response to a discovery signal from the clientsystem.
 10. The apparatus of claim 7, wherein the BMAP unit furthercomprises a format negotiation unit coupled with the modemidentification unit, the format negotiation unit to receiveidentification of data formats.
 11. The apparatus of claim 10, whereinthe BMAP unit further comprises a binding acknowledgement unit coupledwith the format negotiation unit, the binding acknowledgement unit totransmit a poll acknowledgement message to the client system in responseto receiving a poll message from the client system.
 12. The apparatus ofclaim 11, wherein the BMAP unit further comprises a power managementunit coupled with the binding acknowledgement unit, the power managementunit to put the broadband modem into a sleep state in response toreceiving a sleep message from the client system.
 13. The apparatus ofclaim 12, wherein the BMAP unit further comprises a data transfer unitcoupled with the power management unit, the data transfer unit totransfer the ATM cells between the broadband modem and the networkcontroller.
 14. The apparatus of claim 7, wherein the ATM Unit comprisesat least one of the following: a software-based ATM unit and ahardware-based ATM unit.
 15. The apparatus of claim 7, wherein the ATMunit is further to perform at least one of the following: cellconstruction, cell reception and header validation, cell relaying,forwarding and copying, cell multiplexing and demultiplexing, and cellpayload type description.
 16. The apparatus of claim 7, wherein the ATMunit comprises a segmentation and reassembly (SAR) unit to segment andreassemble data between an ATM adaptation layer (AAL) convergencesublayer into cell payloads of an ATM cell stream.
 17. The apparatus ofclaim 16, wherein the ATM unit further comprises an AAL unit coupledwith the SAR unit, the AAL unit to define headers and trailers in an AALpacket.
 18. The apparatus of claim 17, wherein the ATM unit furthercomprises a signaling (SIG) unit coupled with the AAL unit, the SIG unitto set up virtual channels to transmit the ATM cells.